1. Field of the Invention
This invention relates to an alignment sleeve for a fiber otpic connector and connectors incorporating such sleeve.
2. Description of the Prior Art
Precision alignment of one fiber optic cable to another is required to achieve efficient light transfer. This has previously been accomplished in part by providing a tightly fitted tubular sleeve which holds the tips of two mated pins containing the optic fibers in position with one another. To accomplish this tight fit, the tubular sleeve is typically made of a resilient thermoplastic material. The pin tips of the two connectors to be mated together are normally identical in shape. A connector assembly utilizing such a resilient sleeve is disclosed, for example, in U.S. Pat. Nos. 4,140,366 and 4,183,619, the disclosures of which are expressly incorporated herein by reference. In using such alignment sleeves, typically the sleeve is placed around the terminal pin of one of the connectors and the terminal pin of the other connector is inserted into the sleeve during mating to provide a properly aligned connection of the two fiber optic cables.
Although the prior art alignment sleeves have worked quite well, one problem that is experienced is when the connectors are demated and then mated again, as occurs when disconnecting and connecting the fiber optic lines. When the connectors are demated, the resilient sleeve remains attached by friction to one of the terminal pins of the connector. Since the pins are identical in design, nothing predetermines to which pin the sleeve will remain attached. As a result, when a connector is remated with another connector, it may be incorrectly assumed that a sleeve is or is not attached to a pin. Thus, what may occur is the accidental insertion of two sleeves into a connector body which would likely damage the sleeve and impair the alignment, or the accidental omission of a sleeve which would likewise impair the alignment.
It would be desirable to provide a means for eliminating the above mentioned problem.